Abstract:Magnaporthe oryzae(M.oryzae),a hemibiotrophic pathogenic fungus,can infect rice(Oryza sativa) and cause rice blast.The mechanisms involved in resistance of rice to blast have been studied extensively.However,it is difficult to investigate interactions between rice and M.oryzae because of the relatively large genome sequence of rice and the diversity of M.oryzae.The strain of M.oryzae,Y34,was found to be able to infect Arabidopsis thaliana Col-0 plants,so M.Oryzae(Y34)—Arabidopsis thaliana pathosystem was established to investigate the role of Arabidopsis thaliana ENHANCED DISEASE RESISTANCE 1(AtEDR1),which exerts negative regulation on powder mildew resistance by salicylic acid(SA) pathway.The results indicated that edr1 mutant was more susceptible to M.oryzae than wild type Col-0 plants.Previous double mutant analysis revealed that all edr1-associated disease resistance phenotypes were suppressed by mutants that block SA perception(nim1) or reduced SA production(pad4 and sid2).These double mutants were inoculated with Y34 to examine if they would suppress the susceptibility of edr1 to M.oryzae,and the results showed that compared with edr1,all double mutants exhibited resistance to M.oryzae.These data suggest AtEDR1 may play a positive role in the regulation of resistance to M.oryzae in Arabidopsis,which is required for SA pathway.